Discharge printing is a common practice in print making on a dyed fabric. A discharge print paste is applied, in pattern form, to the dyed fabric. The paste pattern is subjected to high temperature steaming which causes the discharge print paste to discolor the dyed fabric to form a white or light colored pattern.
Traditionally a discharge paste is formulated with a combination of compounds such as sodium hydroxide, ethoxylated product and polyols, ethanedoic acid, hydroxyacetic acid, prooanoic acid, botanic acid, polyethylene glycol, polyoxyethylene sorbitan, polyalkaline glycol ether, stannous chloride etc. The discharge print paste is applied to the fabric using screen print, block print, stencil print or any other printing available for paste, for example as disclosed in U.S. Pat. Nos. 4,631,067 and 5,131,915, the contents of which are incorporated herein by reference. However, the discharge print paste, especially of U.S. Pat. No. 5,131,915, requires the use of many components including ethoxylated products, polyols, reducing agents, organic acids, thickening agents and lithium hydroxide. Such a formulation presents problems in handling and disposal of the residue after the printing.
There thus remains a need for a discharge print paste which is environmentally friendly and is simpler to formulate and use.